I spent so much money on home improvements (Window, doors, insulation, AC, furance, water heater, etc.) and I'm only getting $657 instead of max credit of $3200.

I know that you can get max credit of $3200 once a year. I spent $7000 on furance so I should be getting $600 back I spent $3500 on AC so I should be getting $600 back I spent $3500 on insulation so I should be getting $600 back I spent $2500 on new electric circuit and upgrade 150 AMP - I should be getting $600 back I spent more on new doors, windows, etc so I should be getting max credit of $3200 but instead I only got $657 back so what am i missing. I only filled in W-2 form, mortage interest and EIC (one child).